* re-use SdFat value through static const, no need to hard-code our
  values w/ cast in the macro
* separate read-modes from flags
* simple compile-time tests in .cpp

resolve esp8266#8831

mcspr changed the title SdFat <-> FS HAL mode fixes & test SdFat -> FS HAL mode fixes & test

mcspr deleted the sdfs/mode-oops branch

earlephilhower added a commit to earlephilhower/arduino-pico that referenced this pull request

earlephilhower added a commit to earlephilhower/arduino-pico that referenced this pull request

hasenradball pushed a commit to hasenradball/Arduino that referenced this pull request

* re-use SdFat access mode through static const, no need to hard-code our own value w/ cast in the macro
* separate read-modes from flags; read, write and rw are distinct numbers
* simple compile-time tests in .cpp

resolve esp8266#8831